Composite vascular flow diverter

ABSTRACT

A vascular flow diverter includes a tubular mesh framework which includes a mesh cover and an opening. The tubular mesh framework is collapsible and configured to expand from a collapsed shape to a tubular shape when the vascular flow diverter is deployed. The mesh cover conforms to the shape of the tubular mesh, is surrounded by the tubular mesh framework, and is less porous than the tubular mesh framework. The opening is located within the mesh cover. A delivery wire passes through the opening in order to guide the flow diverter into place over an aneurysm.

FIELD

The disclosure relates generally to intravascular medical devices. The disclosure relates more specifically to medical devices for treating vascular trauma and deformities.

BACKGROUND

Current vascular flow diverters consist of low-porosity braids that are deployed across the neck of the aneurysm and cover not only the periphery of the vessel across the neck of the aneurysm, but also a segment of otherwise healthy vessel proximal and distal to the neck of the aneurysm. Thromboembolic complications commonly result from these types of devices. Patients with such devices are prescribed long-term medication to alleviate the risk for device thrombosis.

The ideal intra-luminal flow diverter would treat the neck of the aneurysm only, thus minimizing the amount of metal in the lumen of the vessel and the potential for thromboembolic complications. However, positioning of a neck cover against the neck of the aneurysm in a three-dimensional space under fluoroscopy guidance is difficult with currently available imaging technologies.

No intra-vascular devices are commercially available that minimize the amount of metal in the vessel by targeting only the neck of the aneurysm. There are commercially available devices that attempt to treat the neck of the aneurysm intra-saccular, such as various aneurysm embolization systems (e.g. embolic coils).

SUMMARY

The present disclosure describes various examples of an intra-vascular flow-diverting device designed to minimize the amount of metal in the vessel by targeting only the neck of an aneurysm, devices for deploying the intra-vascular flow-diverting device, and methods for guiding and deploying a flow diverting device to cover the neck of an aneurysm.

In one example of the disclosure, a vascular flow diverter includes a tubular mesh framework which includes a mesh cover and an opening. The tubular mesh framework is collapsible and configured to expand from a collapsed shape to a tubular shape when the vascular flow diverter is deployed. The mesh cover conforms to the shape of the tubular mesh, is surrounded by the tubular mesh framework, and is less porous than the tubular mesh framework. The opening is located within the mesh cover.

In one example, the tubular mesh framework has a circular cross section. In one example, the mesh cover has a rounded perimeter. In another example, the mesh cover has a circular perimeter. In some examples, the mesh cover is integrated with the tubular mesh framework. In other examples, the mesh cover is separate from and attached to the tubular mesh framework. In one example, the mesh cover is attached to the tubular mesh framework by welding. In another example, the mesh cover is attached to the tubular mesh framework by interlacing mesh strands of the mesh cover with mesh strands of the tubular mesh framework.

In one example of the disclosure, a device for deploying a vascular flow diverter includes a hollow microcatheter which includes a tubular outer wall, a distal end, and a proximal end. In one example, the distal end of the microcatheter includes a transverse opening which is substantially perpendicular to a longitudinal axis of the microcatheter and also includes a longitudinal opening which is substantially parallel to the longitudinal axis. The longitudinal opening intersects the transverse opening. The device also includes a delivery wire which includes a distal section, a proximal section, and a junction between the distal section and the proximal section. At least a portion of the distal section of the delivery wire is configured to adopt a curved configuration. The distal section has a smaller cross section than the proximal section.

In one example, the portion of the distal section of the delivery wire configured to adopt a curved configuration is pre-formed into the curved configuration and configured to revert to the curved configuration from a straightened configuration when the distal section of the delivery wire is deployed from the microcatheter

In another example, the delivery wire includes a pull wire. The pull wire is positioned in a lumen of the delivery wire and terminates at a tip of the distal section. A proximal end of the pull wire may be pulled to apply tension to the pull wire, which draws at least a portion of the distal section of the delivery wire into a curved configuration.

In one example, a radiopaque marker may be fixed to the junction between the distal section and the proximal section of the delivery wire. In another example, a radiopaque marker may be fixed to the tip of the distal section of the delivery wire. In another example, the distal tip of the distal section of the delivery wire may be a coil formed from radiopaque material. In another example, a radiopaque marker may be fixed to the distal end of the microcatheter. In one example, the radiopaque marker fixed to the distal end of the microcatheter may be located between the transverse opening and a proximal end of the longitudinal opening. In a further example, the radiopaque marker fixed to the distal end of the microcatheter includes a split ring shape. In another further example, the split of the split ring shape is located astride the longitudinal opening of the microcatheter.

In one example of the disclosure, a method for deploying the vascular flow diverter includes advancing a microcatheter in a distal direction across a neck of an aneurysm in a blood vessel, advancing a distal tip of a delivery wire out of the microcatheter, rotating the microcatheter so that the curved delivery wire tip exits through the longitudinal slot in the microcatheter, which radially aligns the mesh cover to the aneurysm entrance, and guiding the distal tip of the delivery wire into the aneurysm. The method also includes withdrawing the microcatheter in a proximal direction while maintaining a position of the delivery wire so that the self-expanding frame of the vascular flow diverter opens against an inner wall of the blood vessel and the distal tip of the delivery wire guides the mesh cover of the vascular flow diverter across the neck of the aneurysm.

In another example, the method also includes confirming, via a radiological imaging device, that the distal tip of the delivery wire is located inside the aneurysm. In another example, the method includes withdrawing the delivery wire into the microcatheter and withdrawing the delivery wire and the microcatheter from a patient.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a drawing of a flow diverter illustrating its primary components and their relationship to each other, in accordance with the present disclosure.

FIG. 2 is a drawing of a microcatheter for delivering the flow diverter, illustrating its primary components and their relationship to each other, in accordance with the present disclosure.

FIG. 3 is a drawing of one example of a delivery wire for delivering the flow diverter, illustrating its primary components and their relationship to each other, in accordance with the present disclosure.

FIG. 4 is a cross-sectional view of one example of the microcatheter with the delivery wire and flow diverter installed in preparation for placement in a blood vessel, in accordance with the present disclosure.

FIGS. 5a-5f are a series of drawings of an aneurysm in a blood vessel, illustrating an example of a sequence of steps for placing the flow diverter in a blood vessel to occlude an aneurysm, in accordance with the present disclosure.

FIG. 6 is a flow chart illustrating an example of a sequence of steps for placing the flow diverter in a blood vessel to occlude an aneurysm.

FIG. 7 is a drawing of a flow diverter in the collapsed configuration, in accordance with the present disclosure

FIG. 8 is a drawing of a cross-section of the collapsed flow diverter of FIG. 7, in accordance with the present disclosure

FIG. 9 is a drawing of another cross-section of the collapsed flow diverter of FIG. 7, in accordance with the present disclosure

DETAILED DESCRIPTION

Referring now to the Figures, in which like reference numerals represent like parts, various examples of the computing devices and methods will be disclosed in detail.

FIG. 1 is a drawing of a flow diverter 100. The flow diverter 100 includes a self-expanding tubular mesh frame 102, which has high porosity. “High porosity” indicates that the mesh of the component includes more open space than vessel coverage. A high porosity component thus has a low metal-to-artery ratio. The metal-to-artery ratio is calculated by dividing the cylindrical area that the device covers in the artery by the total cylindrical area of the artery segment containing the device. The tubular mesh frame 102 has an expanded (free) state and a collapsed state. The expanded state is shown. The tubular mesh frame 102 must be externally compressed to enter the collapsed state and resumes the expanded state under the proper conditions. In some examples, the tubular mesh frame 102 can automatically resume the expanded state by action of internal tension forces as soon as an external constraint is removed. In other examples, the tubular mesh frame 102 may resume the expanded state in response to a thermal input or an electrical signal. On example of such a tubular mesh frame 102 can be fabricated from shape-memory alloy such as nickel-titanium alloy (nitinol).

A low porosity (high metal-to-artery ratio) mesh cover 104 is incorporated with the tubular mesh frame 102. The mesh cover 104 is placed over the mid-section of the tubular mesh frame 102. The mesh cover 104 generally may have a circular, rounded, or oblong shape 110. An opening 106 is formed in the center of the mesh cover 104. The opening 106 is sufficiently large to allow a guiding device, such as a steerable radiopaque guidewire (or microcatheter) to pass through it.

In some examples, the mesh cover 104 may be integrated as part of the tubular mesh frame 102. In one example, the mesh cover 104 may be woven from the same filaments as the tubular mesh frame 102, but in a tighter pattern. In other examples, the mesh cover 104 may be a separate element attached to the tubular mesh frame 102. In one such example the mesh cover 104 may attached to the tubular mesh frame 102 by welding. In another such example the mesh cover 104 may attached to the tubular mesh frame 102 by an adhesive. In another example, filaments of the mesh cover 104 may be interlaced with the filaments of the tubular mesh frame 102. In another such example the mesh cover 104 may attached to the tubular mesh frame 102 by temporarily and locally melting either the mesh cover 104 or tubular mesh frame to fuse the two together (as opposed to welding, which would temporarily melt both to create the bond). In another such example the mesh cover 104 may be attached to the tubular mesh frame 102 by sandwiching the mesh cover 104 between layers of the tubular mesh frame 104, or vice versa.

FIG. 7 illustrates the flow diverter 100 in the collapsed state. A collapsed portion 700 is formed in the tubular mesh frame 102 and the mesh cover 104 to accommodate a distal end 302 of a delivery wire 300 while the flow diverter is advanced through a microcatheter 200 for placement over an aneurysm (see below for more detail on tools and techniques for delivering and placing the flow diverter 100). FIG. 8 illustrates a cross-section of the collapsed flow diverter 100 through the tubular mesh frame 102 only. The collapsed portion 100 can be seen more clearly in this cross-sectional view. FIG. 9 illustrates a cross-section of the collapsed flow diverter 100 through the center of the opening 106. As such, the relationship between the collapsed portion 700, the opening 106, the tubular mesh frame 102, and the mesh cover 104 can be seen.

FIG. 2 illustrates a microcatheter 200 for delivering the flow diverter 100. The microcatheter 200 has a tubular outer wall 202, a distal end 204, a proximal end 206, and a longitudinal axis 210 which is approximately coincident with the center of the tubular outer wall 202 along its length. The distal end includes a transverse opening 208 and a longitudinal opening 212. In some examples, the transverse opening 208 may be substantially perpendicular to the longitudinal axis 210. In some examples, the transverse opening 208 may be at an angle to the longitudinal axis 210.

The longitudinal opening 212 may be a slot or similar shape having a long dimension following the length of the microcatheter 200 and a short dimension on the circumference (or other non-circular perimeter) of the microcatheter 200. One end of the longitudinal opening 212 intersects 214 the transverse opening 208 at the distal end 204 of the microcatheter 200. The other end of the longitudinal opening may be square (i.e. having right-angle corners with or without radii), semicircular, or elliptical.

The distal end 24 of the microcatheter 200 may also include a radiopaque marker 218. The radiopaque marker 218 allows a clinician to observe the location of the distal end 204 of the microcatheter 200 within a patient's vascular system using a radiological instrument. For example, a clinician may use fluoroscopy, digital subtraction angiography, rotational angiography, computed tomography (CT), cone beam CT, or the like to observe the location of the radiopaque marker 218. In some examples, the radiopaque marker 218 may be a circular band or ring shape. In some further examples, the circular band may be a split ring shape, where the split in the ring is aligned with the longitudinal opening 212.

FIG. 3 illustrates a steerable delivery wire 300 for delivering the flow diverter 100. The delivery wire 300 is deployed within the microcatheter 200. The delivery wire 300 includes a distal section 302, a proximal section 304, and a junction 306 between the distal section 302 and/or the proximal section 304. At least a portion of the distal section 302 of the delivery wire 300 is configured to adopt a curved configuration. The distal section 302 has a smaller cross section than the proximal section 304. In some examples, the distal section 302 can slide relative to the proximal section 304. This allows the tip of delivery wire to be retracted after the flow diverter is placed across the neck of the aneurysm. In some examples, both the distal section 302 and the proximal section 304 have circular cross sections. In other examples, the distal section 302 and the proximal section 304 may have non-circular cross-sections. For instance either of the distal section 302 or the proximal section 304 may have elliptical, oblong, oval, triangular, or quadrilateral cross sections. In addition, in some examples the non-circular cross section of either the distal section 302 or the proximal section 304 may not have a consistent angular orientation along the length of the delivery wire 300. The distal section 302 includes a tip 310. In some examples, the tip 310 may include a radiopaque marker 314.

In one example, the portion of the distal section 302 of the delivery wire 300 configured to adopt a curved configuration is preset into the curved configuration and reverts to the curved configuration from a straightened configuration when deployed from the microcatheter. Thus, the section is in the curved configuration when the delivery wire is in its free state. When the delivery wire is inserted into the microcatheter the inner diameter of the microcatheter constrains the delivery wire and forces the curved portion into a straightened configuration. When the delivery wire is deployed from the microcatheter the section reverts to its preset curved configuration. The curved section may be formed from flexible resilient materials. For example, the curved section may be formed from spring steel or may be heat-treated to form the curved section in its free state.

In another example, at least one pull wire 308 is positioned within the lumen 316 of the delivery wire 300. The pull wire 308 or wires are attached to the tip 310 of the distal section 302 so that when a pull wire 308 is pulled from a proximal end 318 of the proximal section 304 of the deliver wire 300, it causes at least a portion of the distal section 302 near the tip 310 to curve. This allows a clinician to guide the tip 310 of the distal section 302 of the delivery wire 300 into an aneurysm. In some examples, the entire distal section 302 may curve when the pull wire 308 is pulled. In other examples, a portion of the proximal section 304 may also curve when the pull wire 308 is pulled.

The junction 306 between the distal section 302 and the proximal section 304 has a cross section at least as large as the proximal section 304. The junction 306 is used to push the flow diverter 100 out of the microcatheter 200 for placement across the neck of an aneurysm, as will be explained in greater detail below. In some examples, the junction 306 may also include a radiopaque marker 312.

FIG. 4 is a cross-sectional view illustrating the microcatheter 200 with the delivery wire 300 and flow diverter 100 installed in preparation for placement in a blood vessel. The flow diverter 100 is mounted over distal section 302 of the guidewire 300 by guiding the opening 106 over the distal section 302 until the tubular mesh framework 102 meets the junction 306 between the distal section 302 and the proximal section 304 of the delivery wire 300. The tubular mesh framework 102 of the flow diverter 100 is then compressed into its collapsed state, pre-loaded into an introducer (not shown), and transferred into the microcatheter lumen 220.

FIGS. 5a-5f are a series of drawings illustrating one example of a sequence of steps for placing the flow diverter 100 in a blood vessel 514 to occlude an aneurysm 512. At FIG. 5a the microcatheter 200 is advanced across the neck 516 of the aneurysm 512. At FIG. 5b , the radial alignment of the longitudinal opening 212 of the microcatheter 200 with the aneurysm is checked and adjusted, if necessary. The tip 310 of the distal section 302 of the delivery wire 300 is then advanced out of the microcatheter 200 and guided through the neck 516 of the aneurysm 512. The delivery wire may have a preset curvature, as described above, or may be guided using a pull wire 308. The delivery wire is engaged with the implant by passing through orifice 106, but is not attached. At FIG. 5c , after confirming that the tip 310 of the distal section 302 is seated in the aneurysm 512, the flow diverter 100 may be deployed. The flow diverter 100 is deployed by pulling back on the microcatheter 200 while maintaining the position of the delivery wire 300.

At FIG. 5d , the self-expanding tubular frame 102 opens against the interior of the blood vessel 514 while the flow diverter 100 is guided along the distal section 302 of the delivery wire 300 by its opening 106. At FIG. 5e , the flow diverter 100 is fully deployed from the microcatheter 200 and expanded. At FIG. 5f , the delivery wire 300 is withdrawn back into the microcatheter 200 and they can both be withdrawn from the patient.

FIG. 6 is a flow chart illustrating the sequence of steps for placing the flow diverter in a blood vessel to occlude an aneurysm. At 600, the clinician advances the microcatheter in the distal direction across a neck of an aneurysm in a blood vessel. At 602, the clinician advances the distal tip of the delivery wire out of the microcatheter and guides the distal tip of the delivery wire into the aneurysm. At 604, the clinician confirms, via a radiological imaging device, that the distal tip of the delivery wire is located inside the aneurysm. The radiological imaging device may include, for example, fluoroscopy, digital subtraction angiography, rotational angiography, computed tomography (CT), cone beam CT, or the like. At 606, the clinician deploys the flow diverter from the microcatheter. At 608, the clinician withdraws the microcatheter in the proximal direction while maintaining the position of the delivery wire so that the self-expanding frame of the vascular flow diverter opens against the inner wall of the blood vessel while the distal tip of the delivery wire guides a mesh cover of the vascular flow diverter across the neck of the aneurysm. At 610, the clinician withdraws the delivery wire into the microcatheter. At 612, the clinician withdraws the delivery wire and the microcatheter from the patient.

To facilitate an understanding of the principals and features of the disclosed technology, illustrative examples are explained above. The components described as making up various elements of the disclosed technology are intended to be illustrative and not restrictive. Many suitable components that would perform the same or similar functions as components described herein are intended to be embraced within the scope of the disclosed electronic devices and methods. Such other components not described herein may include, but are not limited to, for example, components developed after development of the disclosed technology.

It must also be noted that, as used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise.

By “comprising” or “containing” or “including” is meant that at least the named component, element, or method step is present in the article or method, but does not exclude the presence of other component, materials, elements, method steps, even if the other such component, materials, elements, method steps have the same function as what is named.

It is also to be understood that the mention of one or more method steps does not preclude the presence of additional method steps or intervening method steps between those steps expressly identified. Similarly, it is also to be understood that the mention of one or more components in a device or system does not preclude the presence of additional components or intervening components between those components expressly identified.

The design and functionality described in this application is intended to be exemplary in nature and is not intended to limit the instant disclosure in any way. Those having ordinary skill in the art will appreciate that the teachings of the disclosure may be implemented in a variety of suitable forms, including those forms disclosed herein and additional forms known to those having ordinary skill in the art.

While certain examples of this disclosure have been described in connection with what is presently considered to be the most practical and various examples, it is to be understood that this disclosure is not to be limited to the disclosed examples, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

This written description uses examples to disclose certain examples of the technology and also to enable any person skilled in the art to practice certain examples of this technology, including making and using any apparatuses or systems and performing any incorporated methods. The patentable scope of certain examples of the technology is defined in the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims. 

The invention claimed is:
 1. A device for deploying a vascular flow diverter, the device comprising: a microcatheter comprising a tubular outer wall, a distal end, and a proximal end, the distal end comprising a transverse opening and a longitudinal opening, where the transverse opening is perpendicular entirely along a cross-section of the distal end to a longitudinal axis of the microcatheter and the longitudinal opening is substantially parallel to the longitudinal axis of the microcatheter, and the longitudinal opening intersects the transverse opening; a delivery wire comprising a distal section, a proximal section, and a junction between the distal section and the proximal section, where: the distal section has a smaller cross section than the proximal section; the distal section is steerable from a proximal end of the proximal section, where at least a portion of the distal section of the delivery wire is configured to adopt a curved configuration; and the junction is configured to push the vascular flow diverter; and a pull wire positioned in a lumen of the delivery wire and terminating at a tip of the distal section, where a proximal end of the pull wire may be pulled to form the curved configuration in at least a portion of the distal section, and where the distal section of the delivery wire is sufficiently contiguous to contain, when the pull wire is pulled to form the curved configuration in the distal section, an entire length of a portion of the pull wire extending from the tip of the distal section, through the distal section, and to the junction.
 2. The device for deploying a vascular flow diverter of claim 1, where the portion of the distal section of the delivery wire configured to adopt the curved configuration is pre-formed into the curved configuration and configured to revert to the curved configuration from a straightened configuration when the distal section of the delivery wire is deployed from the microcatheter.
 3. The device for deploying a vascular flow diverter of claim 1, further comprising a radiopaque marker fixed to the junction between the distal section and the proximal section.
 4. The device for deploying a vascular flow diverter of claim 1, further comprising a radiopaque marker fixed to a tip of the distal section.
 5. The device for deploying a vascular flow diverter of claim 1, further comprising a radiopaque marker fixed to the distal end of the microcatheter.
 6. The device for deploying a vascular flow diverter of claim 5, where the radiopaque marker fixed to the distal end of the microcatheter is located between the transverse opening and a proximal end of the longitudinal opening.
 7. The device for deploying a vascular flow diverter of claim 6, where the radiopaque marker fixed to the distal end of the microcatheter comprises a split ring shape.
 8. The device for deploying a vascular flow diverter of claim 1 where the curved configuration of the distal section of the delivery wire is configured to pass through an opening formed in a tubular mesh vascular flow diverter in order to guide the tubular mesh vascular flow diverter into position over a neck of an aneurysm during deployment of the tubular mesh vascular flow diverter. 